1281189985 has 16 divisors (see below), whose sum is σ = 1593720000. Its totient is φ = 987569856.

The previous prime is 1281189971. The next prime is 1281190019. The reversal of 1281189985 is 5899811821.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1281189985 - 2⁹ = 1281189473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63502 + ... + 81208.

It is an arithmetic number, because the mean of its divisors is an integer number (99607500).

Almost surely, 2^1281189985 is an apocalyptic number.

It is an amenable number.

1281189985 is a deficient number, since it is larger than the sum of its proper divisors (312530015).

1281189985 is a wasteful number, since it uses less digits than its factorization.

1281189985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18240.

The product of its digits is 414720, while the sum is 52.

The square root of 1281189985 is about 35793.7143224896. The cubic root of 1281189985 is about 1086.1034128648.

The spelling of 1281189985 in words is "one billion, two hundred eighty-one million, one hundred eighty-nine thousand, nine hundred eighty-five".